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准噶尔盆地深、浅部构造关系及其岩石圈结构动力学模型
程宏岗
Subtype博士
Thesis Advisor赵俊猛
2007-07
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Name博士研究生
Degree Discipline构造地质学
Keyword准噶尔盆地  拆离面  海西期褶皱山系  结晶地壳  隐伏断裂  地震活动  岩石圈结构  地球动力学模型  油气分布
Call NumberB000001
Abstract

The Junggar Basin(JB) is one of the biggest composite petroliferous basins in northwestern China. There are a series of folded mountain systems around the JB, such as the Zhayier Shan and Hala'alat Shan in the northwestern margin, the Altay Shan, Qinggelidi Shan and Kelameili Shan in the northeastern margin, the Eren Habirga Shan and Bogda Shan in the southern margin, respectively. The span of the JB is longer from east to west than from south to north, and the whole basin looks like a triangle. It is well known that the JB is a basin rich in petroleum, especially in its marginal regions. Aiming at the development and evolution characteristics of the JB, a geodynamic model of lithospheric structure of the JB was put forward based on widely summing up preceding research, adopting a whole, dynamic and integrated reasoning and after illuminating the basement structure and property of the JB. The deep structures have a close affiliation with the shallow ones by the processes of the force, substance and heat. After analyzing these three processes in detail, this model also has a control action to the mineral resources (especially the oil and gas) in the JB. Different scholars have different opinions about the basement structure and property of the JB. This study carries out a systemic study on the preceding research, and gives a relative all-sided answer to the basement structure and property of the JB. That is to say, the JB has a continental crustal basement; there is a two-layer basement structure which is composed of the crystalline basement in the Pre-Cambrian and the folded basement in the Hercynian period; the Sange Quan convex in the JB is the boundary between the Manas terrane in the south and the Ulungur terrane in the north, so the basement of the JB has a character of collage; controlled and affected by the S-N trending faults (Manas-Delunshan Fault and Urumqi-Fuhai Fault) in the JB, the crystalline basement has an obvious difference between the east and west. This study mainly indicates that the deep structures have a close affiliation with the shallow structures by the processes of the force, substance and heat. As to the force, there are many kinds of regional tectonic stresses in the margin, basement and crust of the JB: Firstly, the thrust faults are universal both in the northwestern margin, northeastern margin and southern margin of the JB. These thrust faults make a series of structure processes, including decoupling, displacement, overthrust, nappe and fold, happen in the Hercynian stratum around the JB. So, the ambient topography of the JB shows a sharp uplift. The position of the detachment plane will have a different effect on the shallow structures in the JB. Secondly, the bending of the whole crystalline basement and lithosphere in the JB has a close relation with the structure in the cover strata. The lithosphere in the JB represents obviously layered structures, and the thickness of the sedimentary cover is controlled by the distribution of the crystalline and folded basement of the JB. The G interface is undulate consistently with the Moho. All these show that the outline of the JB is affected by the bending of the whole crystalline basement and lithosphere. Thirdly, a series of near S-N and E-W trending faults are found in the basement and the deep crust of the JB. They cut the crystalline basement of the JB into many unequal blocks. These blocks have a process of decoupling, displacement and overthrust in the deep lithosphere. All of these kind processes maybe have an important impact on the sedimentary cover in the hinterland of the JB. The S-N trending extrusion stress is the main cause to the formation of the S-N trending tensional faults, which are the channels for the deep substance moving upwardly. And the deep substance possibly comes from the top of the upper mantle. This is an explanation for the high velocity, high density and high magnetization of the deep substance in the JB. Finally, there are many earthquakes occurred in the margin of the JB, and few in the hinterland of the JB. The earthquake is induced by the movement of the deep substance in the earth. All these earthquakes have an intimate relation with the faults, most of which have an obvious structural background in the deep crust. As to the substance, by using of the basement velocity and density data from joint gravity-magnetic inversion in the JB, and according to the relationship between velocity-density-lithology, this study draws a conclusion that there are more sandstones, granites and basalts than any other rocks in the JB. The acidic rocks and basic rocks co-exist in the basin. So, the basement(including the folded basement and crystalline basement) of the JB is a complex and multi-lithofacies conglomeration. The acidic rocks and basic rocks have some characters of substance in the mantle. They possibly come from the mantle lithosphere and reconstruct the basement of the JB after moving upwardly. This opinion is supported by more evidence from the deep lithosphere. As to the heat, this study gets 5 time sequences of the volcanic activities according to the isotope chronology data of abundant volcanic rocks in the JB. The heat state in the JB not only has an intimate relation with the power in the deep lithosphere, but also is affected by the physical property of the rocks. The terrestrial heat flow data in the earth's surface is a direct reveal to the heat processes in the earth. It contains abundant geological, geophysical and geochemical information. Moreover, the hot wells going with the faults are also a reflection of the heat process in the deep. The seismic tomography also shows that there are heat processes in the deep. Integrating all the above data, a geodynamic model of the lithospheric structure in the JB was constructed in this study. From the structural characteristics in the margin, hinterland and structures after the formation of the basin, this study also gives a commentary to this model. At the end of this paper, the distribution of the oil and gas was discussed according to this geodynamic model. The result shows that the distribution of the oil and gas is controlled by the basement, deep structure, substances and heat in the deep crust.;准噶尔盆地是我国西北部大型复合含油气盆地之一。盆地四周被褶皱山系所围限,西北边界为扎伊尔山和哈拉阿拉特山,东北边界为阿尔泰山、青格里底山和克拉美丽山,南界为伊林黑比尔根山和博格达山,总体形状为三角形,东西长,南北窄,是一个油气资源十分丰富的含油气盆地,目前已发现的油气田,多位于盆地四周边缘。 本文主要针对准噶尔盆地成盆期前后的发展演化特点,在广泛归纳总结前人研究成果的基础上,应用“整体、动态、综合”的研究思路,在明确准噶尔盆地基底结构和属性的前提下,重点对盆地深、浅部构造关系进行了剖析,主要阐述了盆地深、浅部构造之间力的作用、物质的作用和热的作用。在此基础上,建立了盆地岩石圈结构动力学模型,进而讨论了盆地内大量赋存的矿产资源(特别是油气)分布与岩石圈结构的关系。 有关准噶尔盆地的基底结构和属性各家观点不一。本文在前人工作的基础上,对准噶尔盆地,尤其是对盆地的基底结构和属性进行了深入探讨,认为准噶尔盆地的基底属“陆壳性质”;盆地内前寒武系结晶基底和海西期褶皱基底共存,具“双层基底结构”;以三个泉凸起为界,盆地基底是由南部玛纳斯地体和北部乌伦古地体拼贴而成,具“南北拼贴特点”;受两条南北向断裂(玛纳斯-德伦山和乌鲁木齐-福海断裂)控制和影响,盆地东西部结晶基底结构存在差异。 研究认为,准噶尔盆地深部构造对浅部构造活动的制约作用主要是通过力、物质和热三种形式完成。 力的作用 准噶尔盆地周缘、基底以及地壳中存在多种区域构造应力的作用:首先,盆地西北缘、东北缘和南缘三个方向的褶皱山系中普遍发育逆冲断层,这些逆冲断层作用的结果使盆地周边的海西期地层发生拆离、位移、冲断、推覆和褶皱等作用,造成盆地周边的地形急剧上隆,冲断作用的拆离面的深度不同,其影响盆地构造的程度也不同;其次,全盆地结晶地壳和岩石圈的整体挠曲作用控制和影响了盆地沉积盖层的构造和活动,盆地的岩石圈具有明显的分层结构,盆地褶皱基底面(B)和结晶基底面(G)的分布形状总体上控制了全盆地沉积盖层厚度的变化,而G界面与M界面形状在全盆地(除了乌伦古凹陷一带)基本上同步起伏,表明了结晶地壳和岩石圈的整体挠曲变形控制了盆地的整体轮廓和深度变化;再次,在盆地内探测到了一系列近南北向和近东西向(北西西向)的基底断裂和地壳深部断裂,它们联合起来把准噶尔盆地结晶基底分割成数个大小不一的块体,并在深部发生了拆离、位移和向上逆冲等作用过程,影响和作用到盆地腹部的盖层构造。南北向岩石圈规模的“张性”断裂与盆地形成初期的南北向挤压力有关,同时也是深部物质(可能来自上地幔顶部)上涌并侧向侵位,从而成为盆地深部物质高速度、高密度、高磁化强度的根源;最后,在盆地周缘山系的活动过程中,有频繁的中、深源地震活动发生,而在比较稳定的盆地腹部地震活动较少。地震是地球内部物质运动的结果,断层活动诱发了地震,地震发生又促成了断层的生成与发育,因此地震与断层有密切联系,而这些断层大多都有较强的深部背景。 物质作用 利用重磁联合反演方法获取的基底速度以及密度资料,根据速度、密度、岩性关系的实验结果,得出准噶尔盆地基底(包括褶皱基底和结晶基底)以砂岩、花岗岩和玄武岩居多,酸性、基性岩共存,是一个复杂的,多岩相的混合体,而这些基性、酸性深成岩均有幔源物质的特点,推测其可能来自岩石圈地幔,上涌后对盆地的基底进行改造,而对这一认识还有其它更多的深部证据。 热的作用 准噶尔盆地内部的热状态一方面与深部构造活动的能量密切相关,另一方面也受到岩石物理性质变化的影响。利用盆地周缘及腹部大量分布的火山岩,据同位素年代学信息并结合周边造山带火山岩的特征得出5个火山活动时间序列;大地热流是地球内部热作用过程在地球表面的直接显示,它清晰的表明准噶尔盆地的热流值从晚古生代中期急剧下降,但仍比塔里木盆地高出很多,现今热流值显示准噶尔盆地是一个“冷盆”,热流值基本与塔里木盆地持平;此外,在盆地周缘还有一些伴随断裂活动而活跃的温泉,这也是深部热作用的一种表现;地震层析成像也揭示了盆地深部热作用的存在。 基于准噶尔盆地发展演化、基底结构和属性、深浅部构造关系以及岩石圈分层结构,结合自己编制地学断面的实际工作,从盆地周缘构造演化特征、盆地腹部构造特征、成盆后构造特征等三个方面入手,本文构建了准噶尔盆地岩石圈结构动力学模型。 论文的最后,笔者结合自己硕士阶段的专业背景及本论文的应用性研究目标,就准噶尔盆地内油气资源的形成、分布及其与盆地基底结构和属性以及深浅部构造关系做了进一步的讨论,认为盆地基底结构特征与油气差异聚集关系密切、盆地深部构造与油气分布关系密切、盆地深部物质和热等与油气分布关系密切。

Department大陆碰撞与高原隆升重点实验室
Subject Area地质学
MOST Discipline Catalogue理学::地质学
Pages133页
URL查看原文
Language中文
Document Type学位论文
Identifierhttp://ir.itpcas.ac.cn/handle/131C11/1219
Collection图书馆
Recommended Citation
GB/T 7714
程宏岗. 准噶尔盆地深、浅部构造关系及其岩石圈结构动力学模型[D]. 北京. 中国科学院研究生院,2007.
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